Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934759AbeAISId (ORCPT + 1 other); Tue, 9 Jan 2018 13:08:33 -0500 Received: from baptiste.telenet-ops.be ([195.130.132.51]:35098 "EHLO baptiste.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934737AbeAISIb (ORCPT ); Tue, 9 Jan 2018 13:08:31 -0500 From: Geert Uytterhoeven To: Linus Walleij , Wolfram Sang , =?UTF-8?q?Jan=20Kundr=C3=A1t?= , =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Cc: linux-gpio@vger.kernel.org, linux-i2c@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH] gpio: Add missing open drain/source handling to gpiod_set_value_cansleep() Date: Tue, 9 Jan 2018 19:08:21 +0100 Message-Id: <1515521301-4375-1-git-send-email-geert+renesas@glider.be> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: Since commit f11a04464ae57e8d ("i2c: gpio: Enable working over slow can_sleep GPIOs"), probing the i2c RTC connected to an i2c-gpio bus on r8a7740/armadillo fails with: rtc-s35390a 0-0030: error resetting chip rtc-s35390a: probe of 0-0030 failed with error -5 More debug code reveals: i2c i2c-0: master_xfer[0] R, addr=0x30, len=1 i2c i2c-0: NAK from device addr 0x30 msg #0 s35390a_get_reg: ret = -6 Commit 02e479808b5d62f8 ("gpio: Alter semantics of *raw* operations to actually be raw") moved open drain/source handling from gpiod_set_raw_value_commit() to gpiod_set_value(), but forgot to take into account that gpiod_set_value_cansleep() also needs this handling. The i2c protocol mandates that i2c signals are open drain, hence i2c communication fails. Fix this by adding the missing handling to gpiod_set_value_cansleep(), using a new common helper __gpiod_set_value_nocheck(). Fixes: 02e479808b5d62f8 ("gpio: Alter semantics of *raw* operations to actually be raw") Signed-off-by: Geert Uytterhoeven --- The bad gpio commit is in v4.15-rc1 and later. The i2c commit exposing this is not yet upstream, but in i2c/for-next. --- drivers/gpio/gpiolib.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 358bce6e798b476c..7761d632a5b0dd20 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -2927,6 +2927,18 @@ void gpiod_set_raw_value(struct gpio_desc *desc, int value) } EXPORT_SYMBOL_GPL(gpiod_set_raw_value); +static void __gpiod_set_value_nocheck(struct gpio_desc *desc, int value) +{ + if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) + value = !value; + if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) + gpio_set_open_drain_value_commit(desc, value); + else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) + gpio_set_open_source_value_commit(desc, value); + else + gpiod_set_raw_value_commit(desc, value); +} + /** * gpiod_set_value() - assign a gpio's value * @desc: gpio whose value will be assigned @@ -2941,16 +2953,8 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value); void gpiod_set_value(struct gpio_desc *desc, int value) { VALIDATE_DESC_VOID(desc); - /* Should be using gpiod_set_value_cansleep() */ WARN_ON(desc->gdev->chip->can_sleep); - if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) - value = !value; - if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) - gpio_set_open_drain_value_commit(desc, value); - else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) - gpio_set_open_source_value_commit(desc, value); - else - gpiod_set_raw_value_commit(desc, value); + __gpiod_set_value_nocheck(desc, value); } EXPORT_SYMBOL_GPL(gpiod_set_value); @@ -3277,9 +3281,7 @@ void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) { might_sleep_if(extra_checks); VALIDATE_DESC_VOID(desc); - if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) - value = !value; - gpiod_set_raw_value_commit(desc, value); + __gpiod_set_value_nocheck(desc, value); } EXPORT_SYMBOL_GPL(gpiod_set_value_cansleep); -- 2.7.4